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Identifying airborne transmission as the dominant route for the spread of COVID-19

Zhang, Renyi and Li, Yixin and Zhang, Annie L. and Wang, Yuan and Molina, Mario J. (2020) Identifying airborne transmission as the dominant route for the spread of COVID-19. Proceedings of the National Academy of Sciences of the United States of America, 117 (26). pp. 14857-14863. ISSN 0027-8424. PMCID PMC7334447. doi:10.1073/pnas.2009637117.

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Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics.

Item Type:Article
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URLURL TypeDescription Information CentralArticle
Zhang, Renyi0000-0001-8708-3862
Li, Yixin0000-0001-7937-7385
Wang, Yuan0000-0001-6657-8401
Molina, Mario J.0000-0003-2339-3225
Additional Information:© 2020 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY). Contributed by Mario J. Molina, May 16, 2020 (sent for review May 14, 2020; reviewed by Manish Shrivastava and Tong Zhu). First published June 11, 2020. This work was supported by the Robert A. Welch Foundation (Grant A-1417). A.L.Z. acknowledges the support of a fellowship from the Robert A. Welch Foundation. We are grateful to Fang Zhang for the PM_(2.5) data in Wuhan, China. Data Availability: All data relevant to this research are available in the main text and SI Appendix. Author contributions: R.Z. designed research; R.Z., Y.L., and Y.W. performed research; R.Z., Y.L., Y.W., and M.J.M. analyzed data; and R.Z., A.L.Z., and M.J.M. wrote the paper. Reviewers: M.S., Pacific Northwest National Laboratory; and T.Z., Peking University. The authors declare no competing interest. This article contains supporting information online at
Funding AgencyGrant Number
Robert A. Welch FoundationA-1417
Subject Keywords:COVID-19; virus; aerosol; public health; pandemic
Issue or Number:26
PubMed Central ID:PMC7334447
Record Number:CaltechAUTHORS:20200612-143721963
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Official Citation:Identifying airborne transmission as the dominant route for the spread of COVID-19. Renyi Zhang, Yixin Li, Annie L. Zhang, Yuan Wang, Mario J. Molina. Proceedings of the National Academy of Sciences Jun 2020, 117 (26) 14857-14863; DOI: 10.1073/pnas.2009637117
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103889
Deposited By: Tony Diaz
Deposited On:12 Jun 2020 21:49
Last Modified:16 Nov 2021 18:26

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